<?php
    $arr = array("a"=>"A","b"=>"B");
    $arr['c']=&$arr['a'];
    $arr['c']="GG";//此处一改，["a"]也就改了
    var_dump($arr);
    echo $arr['c'];

    echo '<hr>';
    $a = '1';
    $b = '2';
    $c = &$a;

    $c = '33';
    echo $a;
    echo '<br>';
    echo $c;

?>